NOTICES OF NEW BOOKS.
All serious students of zoology—to whom this publication is addressed—will welcome the appearance of another volume of this excellent treatise. The present contribution is written by Dr. Benham, and was mostly completed before the author left England to take up his appointment in the University of Otago, New Zealand. The Platyhelmia represent a natural phylum often submerged by writers under the old and more inexact term "Vermes," and comprise Flatworms (Planarians), with their offshoots, the Flukes and the Tapeworms. A method pursued, as in the previous parts—already noticed in these pages—and again one of the original features, is an historical survey of each class, showing the slow and gradual accumulation of the facts and theories dealt with, and the chief zoologists who have contributed to our knowledge of the group. One of the most interesting questions raised in the volume relates to the Tapeworm, and as to how the life-cycle of these animals, now perfectly understood, conforms to, or illustrates Steenstrup's Theory of the Alternation of Generations. This is very fully discussed, and demands the careful study of those interested in the question.
It is still apparently too often forgotten that it is in such books as the one under notice, and in studies such as it enforces, that the true facts of evolution are to be found, and not by surface impressions or ingenious suggestions. Nothing seems so much in vogue as an acquiescence in the dogmas of a popular evolution designed for the instruction of the man in the street, or for those who like to acquire new ideas on trust. It is, however, probably as true as the facts of evolution itself, that in every civilized country the number of those who have acquired
